QUINTESSENCE, in ancient and scholastic philosophy, the name given to the fifth immaterial element, over and above the four material elements, air, water, earth and fire, which Aristotle assumed to be permeating the whole world, and called obcria: in medieval philosophy this was called quinta essentia, the fifth essence, and by many was considered material and therefore capable of extraction. The ancient Indian philosophers also contain the same idea of a fifth element; thus there were five Sanskrit elements (bhutas), earth, wind, fire, water and aether. In the history of chemistry the name was applied, by analogy, to the most concentrated extract of a substance.